Various industries, such as oil and gas, mining, agriculture and the like utilize equipment and/or methods to separating fluids from materials. For example, in the mining industry, the separation of a desired mineral component from the undesirable gangue of an ore is a necessary and significant aspect of mining. Tailings are the materials left over after the process of separating the valuable ore from the gangue. Mine tailings are usually produced from a mill in slurry form that is typically a mixture of fine mineral particles and water.
Another example of such a separation method is found in the oil and gas industry. For example, oilfield drilling fluid, often called “mud,” serves multiple purposes in the oil and gas industry. Among its many functions, the drilling mud acts as a lubricant for a drilling bit and increases rate of penetration of the drilling bit. The mud is pumped through a bore of the drill string to the drill bit where the mud exits through various nozzles and ports, lubricating the drill bit. After exiting through the nozzles, the “spent” fluid returns to the surface through an annulus formed between the drill string and the drilled wellbore. The returned drilling mud is processed for continued use.
Another significant purpose of the drilling mud is to carry the cuttings away from the drill bit to the surface. The drilling fluid exiting the borehole from the annulus is a slurry of formation cuttings in drilling mud, and the cutting particulates must be removed before the mud is reused.
One type of apparatus used to remove cuttings and other solid particulates from drilling mud is commonly referred to in the industry as a “shaker” or “shale shaker.” The shaker, also known as a vibratory separator, is a vibrating sieve-like table upon which returning used drilling mud is deposited and through which substantially cleaner drilling mud emerges. Typically, the shaker is an angled table with a generally perforated filter screen bottom. Returning drilling mud is deposited at the top of the shaker. As the slurry moves toward a discharge end that may be higher than an inlet end, the fluid falls through the perforations to a reservoir below thereby leaving the solid particulate material behind. The combination of the angle of inclination with the vibrating action of the shaker table enables the solid particles left behind to flow until they fall off the lower end of the shaker table. The above described apparatus is illustrative of an exemplary shaker known to those of ordinary skill in the art.
Screens used with shakers are typically placed in a generally horizontal fashion on a generally horizontal support within a basket or tray in the shaker. The shaker imparts a rapidly reciprocating motion to the basket and hence the screens. Material from which particles are to be separated is poured onto a back end of the vibrating screen and may be conveyed along the shaker toward the discharge end of the basket.
In some shakers, a fine screen cloth is used with the vibrating screen. The screen may have two or more overlaying layers of screen cloth and/or mesh. Layers of cloth and/or mesh may be bonded together and placed over a support. The frame of the vibrating screen is suspended and/or mounted on a support and vibrates by a vibrating mechanism to create a flow of trapped solids on top surfaces of the screen for removal and disposal of solids.